<%@ page language="java" contentType="text/html; charset=GBK"
    pageEncoding="GBK"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GBK">
<title>Insert title here</title>
</head>
<style>
body {
	font-family: "Trebuchet MS", sans-serif;
	margin: 50px;
}
body,html,#before{
	width:100%;
}
.before{
	height:50px;
	width:100%;
	background-color:#FFD700;
	position:absolute;
	left:0px;
	top:0px;
}
</style>
<body>
<div class="before"></div>
</body>
</html>